Vibrating screen



Jwii 26, 1923.-

' B. A. MITCHELL ViBRAIING SCREEN original Filed May 6, 1918 3Shuts-Supt W3 wk #6 MM W, W4 7 1 ,m

June 26, 1923. 1,459,838

B.-A. MITCHELL VIBRATING SCREEN Original Filed may 6, 1918 {Shuts-Shut 2Lm \ml June'26, 1923. 1,459,838

B. A. MITCHELL VIBRATING SCREEN Original Filed May 6, 1919 s Shuts-Sheet5 Patented June26, 1923. I

UNITED STATES PATENT OFFICE.

BENJAMIN A. MITCHELL, or GARFIELD, UTAH, assrenon or TWO-THIRDS T0MINNIE L.,MrroHELL, or MAGNA, UTAH.

VIBRATING SCREEN.

Application filed May 6,1918, Serial No. 232,798. Renewed January 25,1923.

To 055 whom it may concern Be it known that I, BENJAMIN A.

MITCHELL, a citizen of the United States,

residing at Garfield, in the county of Salt' Lake and State ofUtah,'have invented certain new and useful Improvements in VibratingScreens, of whichthe following 13 a specification. I

This invention relates to a vibrat ng screen, and its purpose is toprovlde 1mproved apparatus for use in screening ore,

sand, gravel and various other materials. 7 The principal object of theinvention 1s to provide a screen having improved means for impartingthereto a true vibration as distinguished from aseries of impacts.{inother important object is to provide 1mproved vibrating means locatedin the plane of the screen, whereby true vibration is imparted to thescreen in the plane thereof and a more perfect screening action secured.Still another important feature of the invenln'the drawings Figure 1shows a top plan view of one form of my invention;

Fig. 2 shows a side elevation thereof; Fig. 3 shows a longitudinalsectional view through my improved rotary vibrator;-

Fig. 4 shows anend view of the vibrator; Fig. 5 shows an end view of therotary vibrator member mounted within the casing of'the vibrator; Fig.-6 is-an enlarged detail view showing the clamping means for securing thelateral edges of the screen; and

F 1g. 7 1s a VIGW'SImIlaI' to F1g2, showing the application oftheinvention toa' machine havi plurality of screenin mediumsw' Referring tothe drawings, it will be seen that the invention comprises a rectangularframe 10 which is held in, an inclined position by any suitablesupporting means, such as the supporting arms llpivotally connected at12 to the lower part of the frame, and the extensible supporting members13 connected to the upper part of the frame and provided with clampingmeans 14 by which these arms may be adjusted in length to vary theinclination of the frame. The screen 15 of wire cloth or other suitablematerial is mounted above the rectangular frame 10 and the lower edgethereof is extended over a cylindrical bar or roller 16 carried by theframe. The lower edge of thescreen is then wrapped once around a rod 17located within a pipe 18 having a longitudinal slot 19 in the sidethereof. The rod 17 is of greater thickness than the width of the slot19, so that when a pull isexerted on the pipe 18 in a downwarddirection, the screen is securely clamped between the rod and the wallsof the slot. The pipe 18 is held by two or more clamping bolts 20 havingarms or fingers 20 to extend partially around the 'pipe, and these boltsare extended through suitable apertures in the flange 21 of the frame,being threadedly engaged at their lower ends by the adjusting nuts 22,so that the tension of the screen may be adjusted by varying thepositions of these nuts.

The upper edge of the screen is also wrapped around a rod'23 locatedwithin another slotted pipe 24:, and this last-named slotted pipe isconnected by a belt or other suitable device 25 to the rotary vibratordesignated generally by the numeral 26.- This vibrator is located uponthe upper part of the frame 10, and has its central axis in the sameplane as the screen 15, as will be apparent from an inspection of F ig.2. The mate rial to be screened is fed to the screening medium 15 from afeed box 27 having an opening 28 in the bottom thereof, and an inclinedplate 29 by which the material passing through the opening is directedonto the upper part of the screen.

The unbalanped rotary vibrator 26 may 1 preferably have the general formillustrated in Figs. 3 'and' 4, where it is shown as comcylindrical inform, but are reinforced on their outer sides by longitudinal ribs 32. Ashaft passes through apertures in the Wallsot' the, central housing 3.0and extends therefrom into each of the casings 31. This shaft may bedriven through a belt mounted on theopulley 34 located withinthe housingor, if desired,"the housing 30 may form the casing of an electricmotorhaving its armature located directly on theshaft. At the inner endof each of the casings 31, the shaft 33 has mounted thereon a bearingmember 36 which has an annular wearing V casing 31.

rin 37 secured thereto by a lock-nut 38. Ball-bearings 3,9 aremountedbetween the ring 37 and the annular ring 4. .0.. which is. securedWithin the outer wall of the within thev housing 31. is secured by a key41 to an unbalanced vibrator member 42, which is provided at oppositeends with cylindrical parts 42? forming bearing members to carry theannular rings 43 which cooperate with the outer rings 44 carriedbythe-casing to form annular raceways for the balLbearings 45. Thebearings, thus formed are spaced apart within the casing and thevibratory member 42 is provided with aneccentric projection 42" on I oneside thereof which serves to unbalance the same and causev vibrations tobe imparted to the casin when the vibratory member is rotated. hisunbalancing effect is increased, without unduly extending the pro1ectron4:2", by providing an aperture 42 through the bearing member disposedoppositely tothe projection 42 with respect to the central axis; of themember. The outer end of the vibrator member 42 has a thrust washer 46seated in a recess therein, and this washer has a small projection 46which is adapted,upon lateral movement of the vibratory membexgto coactwith the rounded surface of a steel nut 47 which is mounted in the end,wall'o1' web 31 of the casing 31.

brator 61, which isilocatec b with its central,

lXli .S bSWMiHHY ,midway between .the

P i -1 fi llp e he twd screens 62 and.

"63, which are connected to thecasing of the ll lit h itt: byconnections ste lar t t ose prev ously described ,j and ,W QKh XQ thQ1 1W6I ends over bars or The extremity of the shaft 33 In Fig. of thedrawings, I have illusrollers 65 and connected to the lower end of theframe by adjustable connections 66.

The material is fed to the upper screen,

which may. be of relatively. coarse mesh, from a feed box 68, and thematerial after passing through this screen is subjected to a furtherscreening action by the lower screen (53 which maybe of finer mesh.

In this invention the rotary vibrator may be driven at relatively highspeed either by belt or motor, so that thirty-five hundred vibrationsperminute or, moremay be imparted to the screen from the casing of thevibrator, thus giving the screen a true vibratory action of highfrequency which serves to effectfa more speedy and perfect screeningaction then that accomplished by,

devices heretofore known. An important feature ofthe invention is thatthe vibrations imparted to the screen are true vibrati ons of highfrequency occurring with regularity as distinguished from intermittentim- P ts impa ted t th s r ns, s c as th I which are produced by the useof pneumatic imPfiQt vibrators, and the like. By locating the vibratorin the plane of the screen, the

screen is given a reciprocating action in its own plane, which is foundto be beneficial in securing a perfect screening of the material fed tothe mesh. By changing the inclination of the frame, the rapidity withwhich the material passes downwardly over the screen may be regulatedasdesired; A sheet,

of rubber, or the like, may be inserted between the vibrator casing andthe frame to permit greaterfreedom of vibration,

" Although Ihave shown and described but two embodiments of theinvention for purposes of illustration, it will be understood that maybeconstructed in widely different forms without departing from the spiritof the in e ion as defined in the appended claims.

Wha I claim li t 1. In apparatus of the class described, a screen,supporting means connected to said screen, means located in the planeofthe SCreen for producing high frequency vibrations in a planeperpendicular to the .plane of thescreen, and means for transmittingsaid vibrations to said screen.

2. In apparatus of the class described, a stationary frame, a screensupported by said frame, a rotary vibratory device located in the planeof said screen, means'for actuating said vibratory device to producehigh fr e,quency vibrations. and means connected to said vibratorydeviceand said screen for imparting said vibrations to said screen. 3. Inapparatus of the class described, a finame, a screen supported bysaidframe, a

-,,vibrator casingmounted in the plane of said screen and connectedtheretopindependently-of said frame, alrunba'lanced rojtary membermounted in said vibratory casing, and

, brator casing, and means for rotating said 1 means for rotating saidmember and thereby imparting vibrations to said casing: and said screen-1 t. In apparatus of the class described, a frame, a screen, means forconnecting one edge of said screen to said frame, a vibrator casingconnected to the opposite edge of said screen, meansfor maintaining saidscreen continuously under high tension, an unbalanced rotary membermounted in said vimember at high speed and thereby imparting highfrequency vibrations to said casing and said screen.

5. In apparatus of the class described, a frame, a screen, means forconnecting one edge of said screen to said frame, a vibrator casinglocated in the plane of said screen, means for connecting anintermediate part of said casing to the opposite edge of said screen,means for connecting the ends of said casing to said opposite edgeof'said screen, an unbalanced rotary member mounted in said casing, andmeans for rotating said unbalanced member.

6. In apparatus of the class described, a screen, means for supportingsaid screen, a vibrator casing connected to said screen independently ofits frame, a shaft journaled in said casing, unbalanced rotary membersmounted in said casing and actuated by said shaft, and means connectedto said shaft in said casing for rotating the same.

7. In apparatus of the class described, a stationary inclined screen,means for holding said screen in a stiff rigid condition, means locatedin the plane of said screen for producing high frequency circularvibrations, and means for connecting said last named means directly tosaid screen.

8. In apparatus of the class described, a frame, a screen, a vibratorydevice mounted on said frame and connected to one edge of said screen,means for connecting the opposite edge of said screen to said frame,means for maintaining said screen under high tension, and means foroperating said vibratory device to produce high frequency vibrations insaid screen independently of said frame.

9. In apparatus of the class described, a frame, a screen mounted Withinsaid frame, a vibrator connected to one edge of said screen, a bar overwhich. the other edge of said screen is passed, and adjustable meansconnected to the other edge of said screen below said bar for adjustingthe tension of said screen.

10. In apparatus of'the class described, a screen, a vibrator casing, arotary vibrator mounted in said casing, said casing having a taperedpart, a ring adapted to fit on said tapered part. means for holding saidring on said casing, and means for connecting said ring to said screen.

11. In apparatus: of the class described, a

rotary vibrator comprising a central housing, a shaft extendingthro.-ugh said housing, means mounted in said housing for rotating saidshaft, a casing carried by said housing, a bearing mounted in saidcasing and having said shaft journaled therein, and a otary nembercentri y m unt d po said shaft within said casing for effectingvibration of said casing and housing upon rotation of said shaft.

12. In apparatus of the class described, a vibrator casing comprising acentral hous ing, a shaft extending through said housing, means mountedin said housing for rotating said shaft, casings mounted at oppositeends of said housing and enclosing the ends of said shaft, rollerbearings mounted in said casings and having said shaft journaledtherein, rotary members mounted in said casings and connected to saidshaft, and other roller bearings for said rotary members, said rotarymembers having parts disposed eccentrically With respect to the axis ofrotation of said shaft whereby a vibration is produced in said casingsand said housing by the rotation of said shaft.

13. In apparatus of the class described, a vibrator casing, a memberadapted to be rigidly attached to said casing, a screen, and a platecarried by said member for connecting said vibrator casing with saidscreen.

14. In apparatus of the class described, a screen, a vibrator casinghaving a circular part, a ring adapted to fit over'said circular part,and a plate connected to said ring and engaging said screen.

15. In apparatus of the class described, a vibrator casing, a shaftmounted in said casing, means connected to the central part of saidshaft for actuating it, and unbalanced rotary members mounted on. saidshaft in opposite ends of said casing.

16. In apparatus of the class described, a vibrator casing, a shaftmounted in said casing, means connected to the central part of saidshaft for actuating it, unbalanced rotary members mounted on said shaftin opposite ends of said casing, a screen, and means for connectingopposite ends of said vibrator casing directly to said screen.

17 In apparatus of the class described, a

frame, a vibrator mounted rigidly With reframe, a screen mounted saidcasing for transmitting vibrations therefrom, and a screen connected toand partially supported by said plate.

20. In apparatus of the class described, a

6 vibrator casing means for producin vibrations in said casing, a plateconnectecl to said casing for transmitting vibrations therefrom, ascreenconnected to and partially supported by said plate, and additionaln BENJAMIN A. MITCHELL.

